// Pyramid.cpp
// OpenGL SuperBible, Chapter 5
// Demonstrates Texture mapping a pyramid
// Program by Richard S. Wright Jr.

#include <GLTools.h>	// OpenGL toolkit
#include <GLMatrixStack.h>
#include <GLFrame.h>
#include <GLFrustum.h>
#include <GLBatch.h>
#include <GLGeometryTransform.h>

#include <math.h>
#ifdef __APPLE__
#include <glut/glut.h>
#else
#define FREEGLUT_STATIC
#include <GL/glut.h>
#endif

/////////////////////////////////////////////////////////////////////////////////
// An assortment of needed classes
GLShaderManager		shaderManager;
GLMatrixStack		modelViewMatrix;
GLMatrixStack		projectionMatrix;
GLFrame				cameraFrame;
GLFrame             objectFrame;
GLFrustum			viewFrustum;

GLBatch             pyramidBatch;

GLuint              textureID;

GLGeometryTransform	transformPipeline;
M3DMatrix44f		shadowMatrix;


void MakePyramid(GLBatch& pyramidBatch)
    {
	pyramidBatch.Begin(GL_TRIANGLES, 18, 1);
    
	// Bottom of pyramid
	pyramidBatch.Normal3f(0.0f, -1.0f, 0.0f);
	pyramidBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
	pyramidBatch.Vertex3f(-1.0f, -1.0f, -1.0f);
    
	pyramidBatch.Normal3f(0.0f, -1.0f, 0.0f);
	pyramidBatch.MultiTexCoord2f(0, 1.0f, 0.0f);
	pyramidBatch.Vertex3f(1.0f, -1.0f, -1.0f);
    
	pyramidBatch.Normal3f(0.0f, -1.0f, 0.0f);
	pyramidBatch.MultiTexCoord2f(0, 1.0f, 1.0f);
	pyramidBatch.Vertex3f(1.0f, -1.0f, 1.0f);
    
	pyramidBatch.Normal3f(0.0f, -1.0f, 0.0f);
	pyramidBatch.MultiTexCoord2f(0, 0.0f, 1.0f);
	pyramidBatch.Vertex3f(-1.0f, -1.0f, 1.0f);
    
	pyramidBatch.Normal3f(0.0f, -1.0f, 0.0f);
	pyramidBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
	pyramidBatch.Vertex3f(-1.0f, -1.0f, -1.0f);
    
	pyramidBatch.Normal3f(0.0f, -1.0f, 0.0f);
	pyramidBatch.MultiTexCoord2f(0, 1.0f, 1.0f);
	pyramidBatch.Vertex3f(1.0f, -1.0f, 1.0f);
    
	
	M3DVector3f vApex = { 0.0f, 1.0f, 0.0f };
	M3DVector3f vFrontLeft = { -1.0f, -1.0f, 1.0f };
	M3DVector3f vFrontRight = { 1.0f, -1.0f, 1.0f };
	M3DVector3f vBackLeft = { -1.0f, -1.0f, -1.0f };
	M3DVector3f vBackRight = { 1.0f, -1.0f, -1.0f };
	M3DVector3f n;
	
	// Front of Pyramid
	m3dFindNormal(n, vApex, vFrontLeft, vFrontRight);
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 0.5f, 1.0f);
	pyramidBatch.Vertex3fv(vApex);		// Apex
    
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
	pyramidBatch.Vertex3fv(vFrontLeft);		// Front left corner
    
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 1.0f, 0.0f);
	pyramidBatch.Vertex3fv(vFrontRight);		// Front right corner
    
    
	m3dFindNormal(n, vApex, vBackLeft, vFrontLeft);
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 0.5f, 1.0f);
	pyramidBatch.Vertex3fv(vApex);		// Apex
    
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 1.0f, 0.0f);
	pyramidBatch.Vertex3fv(vBackLeft);		// Back left corner
	
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
	pyramidBatch.Vertex3fv(vFrontLeft);		// Front left corner
    
	m3dFindNormal(n, vApex, vFrontRight, vBackRight);
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 0.5f, 1.0f);
	pyramidBatch.Vertex3fv(vApex);				// Apex
    
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 1.0f, 0.0f);
	pyramidBatch.Vertex3fv(vFrontRight);		// Front right corner
    
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
	pyramidBatch.Vertex3fv(vBackRight);			// Back right cornder
    
    
	m3dFindNormal(n, vApex, vBackRight, vBackLeft);
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 0.5f, 1.0f);
	pyramidBatch.Vertex3fv(vApex);		// Apex
    
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
	pyramidBatch.Vertex3fv(vBackRight);		// Back right cornder

	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 1.0f, 0.0f);
	pyramidBatch.Vertex3fv(vBackLeft);		// Back left corner

	pyramidBatch.End();
	}

// Load a TGA as a 2D Texture. Completely initialize the state
bool LoadTGATexture(const char *szFileName, GLenum minFilter, GLenum magFilter, GLenum wrapMode)
{
	GLbyte *pBits;
	int nWidth, nHeight, nComponents;
	GLenum eFormat;
	
	// Read the texture bits
	pBits = gltReadTGABits(szFileName, &nWidth, &nHeight, &nComponents, &eFormat);
	if(pBits == NULL) 
		return false;
	
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, wrapMode);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, wrapMode);
	
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, minFilter);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, magFilter);
    
	glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
	glTexImage2D(GL_TEXTURE_2D, 0, nComponents, nWidth, nHeight, 0,
				 eFormat, GL_UNSIGNED_BYTE, pBits);
	
    free(pBits);
    
    if(minFilter == GL_LINEAR_MIPMAP_LINEAR || 
       minFilter == GL_LINEAR_MIPMAP_NEAREST ||
       minFilter == GL_NEAREST_MIPMAP_LINEAR ||
       minFilter == GL_NEAREST_MIPMAP_NEAREST)
        glGenerateMipmap(GL_TEXTURE_2D);
    
	return true;
}


///////////////////////////////////////////////////////////////////////////////
// This function does any needed initialization on the rendering context. 
// This is the first opportunity to do any OpenGL related tasks.
void SetupRC()
	{
    // Black background
    glClearColor(0.7f, 0.7f, 0.7f, 1.0f );

	shaderManager.InitializeStockShaders();

	glEnable(GL_DEPTH_TEST);
    
    glGenTextures(1, &textureID);
    glBindTexture(GL_TEXTURE_2D, textureID);
    LoadTGATexture("stone.tga", GL_LINEAR, GL_LINEAR, GL_CLAMP_TO_EDGE);
    
    MakePyramid(pyramidBatch);

	cameraFrame.MoveForward(-7.0f);
    }

///////////////////////////////////////////////////////////////////////////////
// Cleanup... such as deleting texture objects
void ShutdownRC(void)
    {
    glDeleteTextures(1, &textureID);
    }

///////////////////////////////////////////////////////////////////////////////
// Called to draw scene
void RenderScene(void)
	{    
    static GLfloat vLightPos [] = { 1.0f, 1.0f, 0.0f };
    static GLfloat vWhite [] = { 1.0f, 1.0f, 1.0f, 1.0f };
    
	// Clear the window with current clearing color
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

	modelViewMatrix.PushMatrix();
		M3DMatrix44f mCamera;
		cameraFrame.GetCameraMatrix(mCamera);
		modelViewMatrix.MultMatrix(mCamera);

        M3DMatrix44f mObjectFrame;
        objectFrame.GetMatrix(mObjectFrame);
        modelViewMatrix.MultMatrix(mObjectFrame);

        glBindTexture(GL_TEXTURE_2D, textureID);
        shaderManager.UseStockShader(GLT_SHADER_TEXTURE_POINT_LIGHT_DIFF, 
                                     transformPipeline.GetModelViewMatrix(),
                                     transformPipeline.GetProjectionMatrix(), 
                                     vLightPos, vWhite, 0);

        pyramidBatch.Draw();

		
	modelViewMatrix.PopMatrix();

	// Flush drawing commands
	glutSwapBuffers();
    }


// Respond to arrow keys by moving the camera frame of reference
void SpecialKeys(int key, int x, int y)
    {
	if(key == GLUT_KEY_UP)
		objectFrame.RotateWorld(m3dDegToRad(-5.0f), 1.0f, 0.0f, 0.0f);
    
	if(key == GLUT_KEY_DOWN)
		objectFrame.RotateWorld(m3dDegToRad(5.0f), 1.0f, 0.0f, 0.0f);
	
	if(key == GLUT_KEY_LEFT)
		objectFrame.RotateWorld(m3dDegToRad(-5.0f), 0.0f, 1.0f, 0.0f);
    
	if(key == GLUT_KEY_RIGHT)
		objectFrame.RotateWorld(m3dDegToRad(5.0f), 0.0f, 1.0f, 0.0f);
    
	glutPostRedisplay();
    }




///////////////////////////////////////////////////////////////////////////////
// Window has changed size, or has just been created. In either case, we need
// to use the window dimensions to set the viewport and the projection matrix.
void ChangeSize(int w, int h)
	{
	glViewport(0, 0, w, h);
	viewFrustum.SetPerspective(35.0f, float(w) / float(h), 1.0f, 500.0f);
	projectionMatrix.LoadMatrix(viewFrustum.GetProjectionMatrix());
    transformPipeline.SetMatrixStacks(modelViewMatrix, projectionMatrix);
	}

///////////////////////////////////////////////////////////////////////////////
// Main entry point for GLUT based programs
int main(int argc, char* argv[])
	{
	gltSetWorkingDirectory(argv[0]);
	
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH | GLUT_STENCIL);
	glutInitWindowSize(800, 600);
	glutCreateWindow("Pyramid");
    glutReshapeFunc(ChangeSize);
    glutSpecialFunc(SpecialKeys);
    glutDisplayFunc(RenderScene);
        
	GLenum err = glewInit();
	if (GLEW_OK != err) {
		fprintf(stderr, "GLEW Error: %s\n", glewGetErrorString(err));
		return 1;
		}
	

	SetupRC();

	glutMainLoop();
    
    ShutdownRC();
    
	return 0;
	}